First and second annual report of progress by the state geologist and the assistant and chemist on the Geological survey of the state of Iowa (1868)
First and second annual report of progress by the state geologist and the assistant and chemist on the Geological survey of the state of Iowa, together of the state during the years 1866
First and second annual report of progress by the state geologist and the assistant and chemist on the Geological survey of the state of Iowa